OpenMediaVault - OpenMediaVault is the next generation network attached storage (NAS) solution based on Debian Linux.
Rockstor - Rockstor is a free and open source NAS (Network Attached Storage) operating system.
Amahi Home Server - Amahi is a media, home and app server software known for its easy-to-use user interface. Amahi has the best media, backup and web apps for small networks.
unRAID Server - A scalable, consumer-oriented, server operating system.
NAS4Free - NAS4Free is the easiest and quickest way to install an Open Source free NAS server. From home NAS to enterprise network storage, NAS4Free is trusted by thousands of installations every day.
Unraid - Simplicity. Flexibility. Scalability. Modularity. Unraid empowers you to build the system you’ve always wanted using your preferred hardware, software, and operating systems.